<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS盒子模型之边框</title>
</head>

<body>
    border-top border-bottom
    <br>
    border: width style color
    <br>
    border: border-width / border-style / border-color
    <br>
    none hidden dotted点线 dashsd虚线 solid实线 double groove ridge inset outest
    <br>
    border-collapse: collapse;合并相邻的边框
</body>

</html>